Gear-cutting machine



A. L. STEWART, E. W. BULLOCK AND S. H. EARL.

GEAR CUTTING MACHINE.

APPLICATION FILED OCT. 24. 1919.

1,380,937. Patented June 7, 1921.

9 SHEETS-SHEET I.

ATTORNEY A. L. STEWARTfE: BULLOCK AND S. H. EARL.

GEAR CUTTING MACHINE.

APPLICATION FILED ocT.24.1919.

1 80,937, Patented June 7, 1921.

9 SHEETS-SHEET 2- A a; wf wpz 2 2mm WBZZM; r (v SchzgMH.Far

t? A T TOR/V5 Y A. L. STEWART, E. W. BULLOCK AND S. H. EARL.

GEAR CUTTING MACHINE- APPLICATION FILED OCT- 24,1919. 1,380,937.PatentedJune 7, 1921.

9 SHEETS-SHEET 3- may!!! Il/ m Edward .4 TTORNE 1' A. L. STEWART, E. W.BULLOCK AND S. H. EARL.

GEAR CUTTING MACHINE.

APPLICATION FILED OCT. 24.1919.

Patented. June 7 1921.

9 SHEETSSHEET 4 ArtjzurL. tat/art W HEaJfl A TTOR NE y Schuyler A. L.STEWART, E. W. BULLOCK AND S. H. EARL.

GEAR CUTTING MACHINE.

APPLICATION FILED ocr. 24, 1-919.

1,380,937, Patented June 7, 1921.

9 SHEETS-SHEET 5.

0 6'1 mmunmuu 69 gl flirlfku w lg /ar iflwarci W. fiaZZack SCWQFH. EarlI I ATTORNEY A. L. STEWART, E. W. BULLOCK AND S. H. EARL.

GEAR CUTTING MACHINE.

APPLICATION FILED ocT. 24, 1919.

1,380,937, I Patented June 7, 1921.

9 SHEETSSHEET 6.

J g: a mmww fz Edward i i/ 115061 6 M yZerflLFa-r A TTORNE) A. L.STEWART, E. W. BULLOCK AND S. H. EARL.

GEAR CUTTING MACHINE.

APPLICATION FILED OCT. 24, 1919.

1,3 0,937, Patented June 7, 1.921..

9 SHEETS-SHEET 7.

[N Vi /Woks 5.2 E 'Q .SCWZeI'EEar& I ATTORNEY A. L. STEWART, E. W.BULLOCK AND S. H. EARL.

GEAR CUTTING MACHINE.

APPLICATION FILED OCT. 24, I919.

Patented June 7, 1921.

9 SHEETS-SHEET 8.

1 L Arlm .A. L. STEWART, E. W. BULLOCK AND S. H. EARL GEAR CUTTINGMACHINE.

APPLICATION FILED OCT 24,1919.

1,389,937 Patented June 7, 1921.

9 SHEEISSHEET 9 [/VVENTORS Ida/(L1 Sohuy rlLEar which the following is aspecification.

UNITED STATES PATENT OFFICE.-

.ARTHUR L. STEWART, EDWARD W. BULLOCK, AND S CHUYLER H. EARL, OF

ROCHESTER, NEW YORK, ASSIGNORS TO NEW YORK, A. CORPORATION OF NEW YORK.

GLEASON WORKS, OF ROCHESTER,

T 0 all whom it may concern:

Be it known that we, ARTHUR L.I STEW- ART, EDWARD W. BULLOCK, andSCHUYLE EARL, citizens of the United States of America, residing atRochester, in the county of Monroe and State of New York, have inventedcertain new and useful Improvements in Gear-Cutting Machines, of

The present improvements have to do more particularly with machines-intended for the production of bevel gears, although there are.features ofthe invention which are equally applicable to other types ofgear cutting machines. In a. more particular aspect, the inventionrelates to machines of the reciprocating tool type, and in which thereis a relative generatlng or rolling motion between the tool and the gearblank, in.

order to effect theoretically correctshaping of the profile or crosssection of a tooth, but

in some aspects, the invention is applicable machines, in which latterthe teeth are merely roughed out, leaving the sides straight andunfinished.

In machines of this class, the customary procedure is to complete onetooth or one side of a tooth, and then separate the. gear blank and thetools, to permit indexing the blank, and one of the purposes of theinvention is to provide a machine with bracing means that will serve tohold the gear blank,

and tools rigidly in their proper relative positions while cutting agear, and at the.

same time permit the relative separating movement When indexing takesplace.

Another object of the improvement is to afford an arrangement ofindexing mechanism that will impart stability and" rigidity totheapparatus as a whole, and also provide a simple and practical method ofoperation.

A further purpose of the invention" is to afford means for readilyadapting the machine either to rough out an uncutblank,

or to cut and finish a blank'which-has already been rou-ghed, and theimprovement includes means for modifying the relative feeding motions ofthe toolsand gear blank, so as to meet the requirements of either aroughing or finishing operation.

An adidtional object which is contem plated in the invention is toprovide an im- Specification of Letters Patent.

broken away.

Patented J uneY, 1921.

Application fi led October 24, 1919. Serial No. 333,014.

' proved form of reciprocating tool mechanlsm, by which a toll is heldrigidly in cutting position,-and all chatter prevented during thecutting stroke, and is movable 'during the return stroke to withdraw itfrom engagement with the blank.

he invention consists in certain other improved features andnovelconstruction,

. as will appear clearly fromthe following opposite direction fromFig. 1wit-h parts I Fig. 5 is a diagrammatic view showing the arrangement ofgearing for operating the parts. I I

F g. 6 is a partial end elevation.

Fig. 7 of Fig. 6.

F "g. 8 is ing toward the adjacent'end of Fig. 7

a detail view in elevation look-' is a sectional view on line 7--7 Fig.9 is a detail sectional View, partially in elevation taken generally online 9-9 of Fig. 2.

Fig. 10 is a plan view, partially in section, taken generally on line"1010.of Fig. 6.

Fig. 11 is a sectional view on line 11-1l of Fig. 1.

F 12 is a sectional view on line 12-12 of Fig. 3. i i

Fig. 13.is' a planmechanism appearing in Fig. 12.

Fig-14 is a sectional view on line 14-14.- of Fig. 3. Fig. 15 is of Fig.13.

' Fig. 16. is. a side elevation mechanism andtool carriage.

Fig; 17 is an enlarged side view of one of the tool boxes. I

Fig. 18 is an enlarged plan view of the parts appearing in Fig. 17.

Fig; 19. is an enlargedsectional-view on line 19- 19v of Fig. 18.

view of part of the of the tool Fig. '20 is a transverse sectional viewon line 2020 of Fig. 16. a Referring more particularly to the drawings,which are intended merely as illus-- trative of a practical embodimentof the improvement, and do not limit the invention to the details;disclosed, 1 desi 2 is a cutter support, and 3 is a lank carrier,

7 as shown in Figs. 1, 3 and 4.

For a preliminary understandingof the apparatus it is to be understoodthat during cutting, the gear blank rotates about its own axis, andduring such rotation, the tool or tools, preferably operating onopposite sides of the same tooth, are reciprocate'd, and also movedbodilyso as to-traverse the simultaneously rotating blank, in a mannercorresponding to the relative motion of a rack upon a gear, as wellknown in the art of producing cars by the rolling or generating method.or a convenient understanding of the operation, themechamsm forreciprocating the tools and-imparting the necessary traversing motionthereto will first be de-' scribed.

There aretwo tool slides namely4 and 5, (see Figs. 1, 3, and 16) each ofwhich is provided with tool mechanism mountedthere'on as will bedescribed later in detail; The tool slides are mounted upon anoscillatory cutter carriage 6 so as to reciprocate thereon,

and are adjustable so as to be adaptable to v bevel gears with varyingpitch angles. To

- accomplish this,the,slide 4 travels back and forth in an arm 7 whichis fixedly bolted to the carriage 6 while the slide 5 travels back andforth in an arm 8 which isadjustably attached to the carriage 6 so as tobe fixed at different angles with reference to the arm 7. One means forsuch adjustment is shown,

consisting of a segmental rack 9 secured to an extension on the carriage6 (see Figs, 16 and 20) and an adjusting worm 10 carried by the arm 8and acting to hold the arm in the posltion to which it is adjusted onthe carriage 6. The tool slides 4 and v5 are reciprocated by mechanismthat willnowjbe set forth in detail, and by which the oscillation of thecarriage 6 is effected toimpart the necessary traversing-motion to thetools during a cuttin operation.

he tool slides are. reciprocated b means of an oscillating gear 11 (seeigs. 3

and 16) which engages racks 12 secured-upon the respective tool slides.The ear llis carried by a spindle13 (see Flgs. 3, 12

and 14). and the spindle. 13. carries a pinion '14 which is oscillatedby a rack 15, the latter being eccentrically and adgustably mounted onthe crank-plate 16. The crank-plate 16 is rigidly connected with a gear17 and the latter engages and is driven by a pinion 18 which forms partof an arbor to which is also fixeda pinion '19. The pinion 19 is drivenbv a' gear 20, keyed ates a bed,

tothe shaft 21 (see- Fig. 3), and the shaft 21 has fixed thereon themam-drive pulley 22 to WhlCh ower is applied for operating the variousparts of the .machine. The

mechanism and gearing for imparting oscilla-tin' motion to the cuttercarriage 6, W111 .now

e described. 1 To accomplish this, the shaft 21 carries a bevel gear 23(see Fig. 3) which engages a bevelgear- 24 mounted upon a verticalspindle 25. The latter is provided with a bevel pinion 26 at its lowerend, driving a meshing pinion 27. which is keyedto the shaft 28, and theshaft 28 is provided at its outer end with a pinion 29 (see Figs. 3 and5). Pinion 29 drives inion 30-011 a stub shaft, which also carries apinion 31 engaging the gear 32 on shaft 33.. The shaft 33 is provided atits'opposite end with-a pinion 34 (see Figs 5 and 10) and pinion 34engages and drives the'gear 35 which is fixed on the shaft 36. The shaft36. drives the shaft 37 through reversing mechanism which includes ears38 and 39 for operating the shaft 37 -m one direction, and ears 40, 41and 42 for operatin the shaft .3 in the opposite directlon. he gears 39and 42. are alternately lockedto the shaft 37 to drive the latter, bysuitable reversin mechanism, designated generallyat 43. he detailsofthis reversing mechanism constitute no part of the present invention,and may be in accordwith previous structures for operating a toolcarrier or a blank carrier in opposite directions, suchas illustratedand described in Patent No. 1,203,608November 7, 1916. The shaft 37carries pinion 44 which engages ear 45 onshaft 46. The latter in turnhas 1 red thereon a pinion. 47 engaging the gear 48 which is slidablykeyed on spindle. 49

(see Figs. 5 and 7). The spindle 49 carries tated about its axis, firstin one direction and then in the other, and the particular mechanismforvac'complishlngthis will now be explained.

The blank carrier includes ablank supporting spindle 56 to which the earblank 57 is attached '(see Figs. 1 and 3 aS usual in this-class'ofmachinery. Fixedupon the blank supporting spindle 56 is a worm wheel 157 (see Figs. 3 and 4) which is engaged" and driven by the worm 58mounted upon shaft 59. The worm. shaft 59 is also provided with a bevelpinion 60 (see Figs. 1 and and 8). Gear 76 is driven by pinion 77 2)which is engaged and driven by the cooperating pinion 61 on thetelescopic spindle 62. At its opposite end, the spindle 62 carries thebevel pinion 63 and the latter is engaged and driven by the pinion 64 oninclined shaft 65 (see Figs. 1, 2, and 9). The shaft 65 is provided atits inner end with a bevel gear 66 which is engaged and operated by thebevel pinion 67, the latter being secured'on the vertical, centrallyarranged shaft or spindle 68 which carries at its lower end the bevelpinion 69. Pinion 69 is engaged and driven by bevel gear 70 on the shaft71. The shaft 71 carries a bevel pinion 72 which is engaged and drivenby a bevel gear73, the latter belng fixed to the differential housing 74(see Figs. 1, 5, and 9). The differential housing 74 has journaled inone side thereof an arbor 75 to which is keyed a gear 7 6 (see Figs. 5,7,

fixed on a shaft which also carries a gear 78 that is engaged andoperated by pinion 79, the latter being. fixed on the aforementionedreversing shaft 46. By this means, when the reversing shaft 46 isv movedin opposite directions by means of the reversing mechanism 43, andthereby oscillates the cutter carriage 6, it also transmits a likemotion through one side of thedifierential housing 74, and the gearingjust described, to the blank spindle and gear blank mounted thereon,causing the latter to turn about its axis, first in one direction andthen in the other until one cycle of cutting operations is complete,whereupon the gear blank and tools are separated, and the gear blank isautomatically indexed to present another tooth to cutting position.

Before the indexing operation can take place, it is necessary to effecta separating motion between the gear blank and tool support. Thefollowing description sets forth the mechanism by which this move mentof the blank carrler is accomplished.

Referring to Figs. 2,and 3, the blank carrier 3, is mounted on abase-plate 80 which swings about the vertical center of the machine,occupied by the aforesaid shaft 68.

Movement of the blank carrier back and forth, toward and from the toolsupport, is accom lished by a cam shaft 81 (see Figs. 4 and 11 saidshaft carrying a controlling cam which will be described more fullypresently, and which engages aprojection or pin 82 that is connected formovement with the base-plate 8 0 of the gear blank carrier. The camshaft 81 carries at one end a worm wheel 83 which is driven by the worm84 and the latter is fixed upon a shaft 85 carrying at its oaposite enda gear 86 (see Figs. 5 and 10). ear 86 is engaged and operated by pinion87 which in turn is driven by the gear 88 fixed upon the aforesaid shaft36, which latter is driven continuously in one direction from the maindriving pulley as already described.

The previously mentioned cam, which is fixed upon the cam shaft 81, andcontrols movement of'the blank carrier toward and from the tool support,to permit indexing of the gear blank, is constructed and adjustable tomake the machine readily adaptable for either a roughing or a finishingoperation. For roughing out an uncut blank, it is necessary that thegear blank feed in slowly toward the cutters during the reciprocatingmovement of the cutters, and when the blank carrier has fed sufficientlyfor the cutters to reach the full depth of the tooth, the blank carrieris with drawn from the tool support preferably by a quick movement, andthe blank is then indexed. In a finishing operation, however, where theteeth have "been previously roughed out on another machine, it isdesirable to feed the blank carrier quickly toward the tool supportuntil the tools have reached a full depth position, andthe subsequentcutting takes place principally on the sides of the teeth, to producethe proper tooth curve or profile, and at the end of such finish cuttingoperations, the blank carrier and gear blank are withdrawn from thetools and the blank is indexed. It is sometimes desirable to change amachine from roughing to finishing operations, and to accomplish this,the. cam, designated generally by 89, (see Fig. 11) includes two camways or slots, one designated at 90 for the finish-cutting operation andthe other designated at 91 for the rough-cutting operation. These camways are separated by a wall 92, which is cut away at 93, to permit theaforementioned pin or projection 82 (see Fig. 4) tube readily broughtinto operative relation with either cam way. The cam 89 is adjustablelengthwise on the cam shaft 81 for the purpose just described, and

to this end there is provided an adjusting after every complete cycle ofcutting operations upon a tooth. While the blank'is disengaged fromthetools, it is turned quickly, or indexed, to bring another tooth intocutting position, and the parts for carrying out the indexing operationwill now be described.

The indexing mechanism is mounted on the bed 1, and at predeterminedintervals operates the vertical shaft 68 and other gearing leading tothe blank supporting spindle,

in order to drive the latter at an increased rate of speed, and turn itsufiiciently to index one tooth. The indexing mechanism may be of anyknown type and its particularconstruction forms no part of the presentinvention. It is suflicient for'the purposes of this disclosure todesignate the indexing mechanism generally by 97 (see Figs. 1, 5 and10), and it is operated from shaft 85 through gear 98 fixed thereon andgear 99 which leads to the indexing mechanlsm. Movement of the indexingmechanism, when it is tripped, is transmitted through gears 100,101,102, and 103 (see Figs. 1 and 5) to the spindle 104 which isjournaled'in one sid of the differential housing 74 and has fixedthereon the bevel pinion 105. The bevel pinion 105 engages pinions 106and 107 which are'journaled in the differential case, and the pinions106 and 107 engage the bevel pinion 108 which is fixed on the spindle 75(see Fig. 5). The index mechanism is tripped off intermittently in theusual manner, as by a pivoted lever 109 (see Fig. 1) which is controlledby a cam wheel 102. By this means, when the lever 109 and indexmechanism is actuated one in every revolution of the "cam shaft 81, anadditional movement is imparted to shaft 71, through the differentialgears 105,106, 107 and 108 from spindle 104, (see Fig. 5) and thisadditional motion is transmitted to the blank supporting spindle and theblank is thereby turned far enough to be indexed through the space ofone tooth.

The cam wheel 102 also serves to'control the reversing mechanism 43already mentioned, through the intermittently operated connecting rod110 and lever 111.'

It is essential in a'machine of this class, that'the parts besufficiently rigidto maintain proper relation between the tools and thegear blank at all times, in order to prevent chatter and produce uniformteeth, and to assist in this accomplishment, there are provided bracingmeans connecting. the

' blank carrier and the cutter support at a point on th opposite side ofthe gear blank from the bed, so that in the completed assemblage, thegear blank'and tools are disposed between the bed and such bracingmeans. This bracing means must be such as to permit the necessaryrelative movement of the blank carrier and cutter support, for indexing,and preferably comprises a pair of bracing members secured to the cuttersupport and blank carrier and connected together so as to partake of thesame relative swinging motion that occurs between the blank carrier andcutter support.

The bracing means consists of overhead bracing members 112 and 113connected together by a pivot pin 114 which is in line with the centralshaft 68, or vertical center of the machine. The brace 113 is fixedlyatdexlng.

tached to the top of the cutter support 2 and the brace 112 isadjustably connected to the blank carrier 3. To this end, the blankcarrier is provided with an adjusting pinion 114, (see Fi 1 and 8) whichen ages a rack 115 carried by the brace 112. he adjusting pinion 114 ismounted on a spindle which has a square head 116 at its outer end (seeFig. 2) by which the desired adjustment of the brace 112 is obtained, topermit of moving the blank carrier to the'proper osition with relationto the cutter support in setting up, dependin upon the size of the blankbeing cut. The brace 112 ,is slidable in guides 117. By means of thepivotal connection between the bracing members 112 and 113, justdescribed, the blank carrier is free to swing about the vertical center68 during the indexing operation, and is nevertheless held rigidly inproper relation to the cutter support, and such a bracing means lends amaximum of stability andruggedness to the apparatus without interferingwith its normal operation. Owing to the arrangement of the arms 7 and 8on the cutter carriage 6, considerable resistance is offered to theoscillation of the carriage when the tools and their supporting arms areswinging upwardly inithe generating motion. In order to lessen thisresistance, and to counter-balance the cutter carriage, a balancingweight 118 is provided, see Fig. 2, connected to a cable 119, whichpasses around pulleys 120 and is secured to the cutter carriage.

When the apparatus is used only for rough-cutting, no generating motionof the tools or gear blank is required, and the only movements whichtake place during cutting are the reciprocating motions of the tools105. and the feeding in movement of the blank carrier, the blank andblank spindle being held fixed against rotation, except when in- Underthese conditions, it is necessary to hold the cutter carriage andsegment 54 (see Figs. 5 and 12) stationary and also the blank spindle.This is accomplished by removing the gear 45 from the shaft 46 '(seeFig. 5)'to disengage it from gear 44, and applying to the shaft 46 anysuitable locking means that will hold it against movement. The gear 48ma be disengaged from gear 47, to permit 0 adjusting the cutter supportwhen setting up, and this is accomplished by a shifting lever 121 (seeFig. 7) which controls a sliding collar connected with the gear 48.

The tools and tool slides are constructed and mounted in the mannershown in Figs. 1, 3 and 16 to 20 inclusive. Each of the tool 125supporting arms 7 and 8 is provided with undercut portions or dovetailguide ways. 122, the tool slides being similarly formed ,to engage saidways and being supported on 126' and is limited in itsmovement byengagement with the wall 127 as shown in Fig.

F ig. 1. Each of the tool slides is provided with an adjustable wedgemember I123for taking up any lost motion or wear between the slide andthe arm. Each tool slide has bolted thereto atool box 124 and .mountedtherein is the pivoted clapper block'125 which is mounted to swing aboutthe axis 18. The tool 128 is held in place on the clapper block by abinder plate 129 and bolts 130 which retain the tool against the toolholder 131, the latter engaging a wedge 132. As the slide travels backand forth, the clapper block and toolare oscillated about the axis 126in order to present the tool in cutting position to the blank during thecut-I ting stroke, and to withdraw the tool fromthe blank during thereturn stroke, as well known in this class of machinery. One difficultyhas been to obtain this pivotal motion and at the same time hold thetool rigid during the cutting stroke and prevent chatter. This isaccomplished in the present embodiment by a construction whicheffectually takes up any lost motion, and holds the tool. tightly by awedging action during the cutting stroke. The swinging movement of theclapper block, is accomplished by a connecting device comprising a rod133 which is slidable in a friction clamp 134:, whereby when the toolslide travels on its return stroke, the tension exerted on theconnectingrod'133 rocks the clap-per block so as to withdraw the tool,and during the cutting stroke,

sufficient pressure is exerted on the connecting device 133, to rock theclapper block in the opposite direction and move the tool into cuttingposition.

To bring about the desired wedging action referred to above, the clapperblock 125 is provided with an opening or recess 134 .(see Fig. 18) theopposite operating surfacesof which are inclined to the direction oftravel of the tool slide. Cooperating with the recess 13% is an angulartongue or projecting portion 135 which is connected to or carried by theconnecting rod 133. The tongue 135 loosely engages recess'lB l and isprovided with opposite surfaces that are correspondingly inclined to thedirection of travel of the tool slide. As the connecting rod 133 isforced toward the clapper block 125, the latter is held in its outermostposition by means of the cooperating inclined surfaces, the tongue 185acting as a wedge on the clapper block and serving to prevent theslightest chatter, any lost motion being taken up automatically by thenecessary additional inward movement of the tongue During the returnstroke, the connecting rod 133 is withdrawn with relation to the clapperblock, and the outward movement of the tongue 135 causes a correspondlnginward movement of the clapper block which withdraws the tool from thework.

The present application is intended'to include any modifications,changes, or equivalent structures coming within the principles andunderlying features of the invention, as

comprehended by the following claims.

We claim:

.1. In a gear cutting machine, the combination with a. blank carrier andcutter-support, one movable toward and from the other, of areciprocating cutter on the cutter support, and bracing members securedto the blank carrier and cutter support and connected with each other soas to permit relative movement, said bracing members being located abovethe blank and cutter.

2. In a gear cutting machine, the combination with a blank carrier andcutter support, one mbvable toward and. from the other, of areciprocating cutter on the cutter support, and bracing members locatedabove the blank and cutter and secured to the'blank carrier and cuttersupport, said bracing members being connected together to permitrelative movement and one of them being adjustable with reference to itssupport. a

. 3. Ina gear'cutting machine, the combination with abed, of a blankcarrier and cutter support mounted thereon, one having a movement abouta vertical axis toward and from theother, a reciprocating cutter on thecutter support, and bracing means connecting said blank carrier andcutter support at their upper portions and permitting the.aforementioned swinging motion." I

4. In a gear cuttin machine, the combination with a bed, 0 a blankcarrier and cutter support mounted thereon, one movable about a verticalaxis toward and from the other, a reciprocating cutter on the cuttersupport, and bracin I to the upper portions 0% the blank carrier andcutter support, said bracing members being connected for relativepivotal motion about the aforesaid vertical axis.

5. In. a gear cutting machine, the combination with a blank carrier andcutter sup port, of a. reciprocating cutter on the cutter support, a bedon one side thereof, the

blank carrier and cutter support having relative swinging motion, onetoward an from the other, and braclng members secured to the other sideof the blank carrier members secured bers secured to the blank carrieran cutter support on the other side thereof, said bracing members beingpivotally connected for relative swinging movement about the aforesaidaxis and one of them being adjustable on its support. v

7 In a gear cutting machine, the .combi nation with a guide, of a cuttercarriage mounted on said guide, means for oscillating the cuttercarriage, and a pair of rec1procating tools mounted on the-cutter car-'riage. 8. In a gear cutting machine, the combination with a blankcarrier, of a clrcular guide, a cutter carriage having oscillatorymovement on said circular guide, and a pair of reciprocating toolsmounted on said carriage. I

9. In a gear cutting machine, the combination with a'circular guide, ofa circular cutter carriage having oscillatory move- 'ment on said guide,a pair of reciprocating tools mounted on said carriage, and a blankcarrier movable toward and from the cutter carriage to permit indexingof a blank.

10. In a gear cutting machine, the combination with an oscillatorycutter carriage, of a pair of arms mounted on said carriage, one of'saidarms being fixed and the other adjustable on the carriage to vary theangle between the arms, slides mounted to travel in said arms, and toolsmounted on the slides.

11. In a gear'cutting machine, the combination with a bed and a cuttersupport arranged thereon, of a blank carrier mounted on the bed, a blanksupporting spindle, gearing for rotating the blank supporting spindle,said gearing including a differential housing, generatingmechanismoperating to turn said housing and blank spindle,

' and indexing mechanism arranged on the bed and operatingintermittently to turn said differential housing and blank spindle at asufficient speed to effect indexing. I

12. In a gear cutting machine, the combination with -a. bed and a cuttersupport ar-' ranged thereon, of a blank carrier mounted on the bed, ablank supporting spindle on the blank carrier, gearing'for rotating theblank supporting spindle, said gearing including a centrally arrangedvertical shaft, and a differential housing, generating mechanismoperatin to turn said housing and blank spindle, s owly during thecutting operation, and indexing mechanism mounted on the bed acting torotate said differential housing and blank spindle intermittently at asufficient speed to effect indexing whilethe cutter is disengaged fromthe blank.

13. In a gear cutting machine, the combination with a bed, of a blankcarrier and cutter support, one movable toward and from the other topermit indexing, a blank supporting spindle mounted onthe blank carrier,gearing for rotating the blank supporting spindle, saidgearmg includinga differential housing, generating mechanism.

operating to turn-said housing and blank spindle, and indexing mechanismsupported on the bed and operating to rotate said dif:

ferential housing and blank supporting spindle intermittently atsuflicient speed to effectindexing. 1 14. In a gear cutting machine, thecombination with a blank carrier and cutter sup- 15. In a gear cuttingmachine, the combi-' nation with a blank carrier and cutter .support,one movable toward and from the other for feeding the tools andpermitting indexing, of a cam shaft and cam thereon governing saidrelative movement, the cam having two separate cam ways and beingadjustable on the cam shaft to bring either of said ways into operativeposition.

16. 'In a gear cutting machine, the combination with a blank carrier andcutter support, one movable toward and from theother for feeding thetools and permitting indexmg, of a cam shaft and cam thereon controllingsaid relative movement, the cam including two separate cam ways one ofwhich is used for a roughing operation and the other of which is usedfor a finishing operation, a wall separating said cam ways, said wallhaving'a cut-away portion therein to permit of moving the cam withrelation to a cam controlled projection so as to bring either cam wayinto operative relationship with said projection, and adjusting meanscooperating with the cam for changing its position on the camshaft.

17. In. a gear cutting machine, the combination with a cutter support,of a blank spindle, generating mechanism, means for rotating the blankspindle including a differential housing which is turned slowly duringthe cutting operation by the generating mechanism to impart a generatingmotion tothe blank, indexing mechanism, and connections between theindexing mechanism and the differential housing, whereby nism operatingthrough the opposite side of the differential housing to drive saidhousing and gearing.

19. In a gear cutting machine, the combination with a bed, of a blankcarrier and cutter support arranged thereon, a blank spindle mountedon'the blank carrier, means for driving the blank spindle including adifferential housing located on the bed, generating mechanism operatingto drive said housing and blank spindle, and indexing mechanismoperating intermittently .to

} quickly drive said housing and blank spindle.

20. In a gear cutting machine, the combination with a bed, of a blankcarrier and cutter support arranged thereon, a blank spindle on theblank carrier, means for driving the blank spindle including a centrallyarranged vertical shaft, differential gearing mounted on said bed foroperating the aforesaid vertical shaft and including a housing,generating mechanism operating to drive said housing and vertical shaftslowly, and

indexing mechanism operating intermit-.

tently to drive said housing and vertical shaft quickly for indexing.

21. In a gear cutting machine, the combination with a blank carrier andcutter support, one movable toward and from the ative movement.

22, In a gear cutting machine, the combination with a blank carrier andcutter support, one having swinging movement about a vertical axistoward. and from the other,

of bracing means connecting the blank car- I rier. and cutter support attheir upper portions and permitting the aforementioned swingingmovement.

23. In a gear cutting machine, the combination with a blank carrier andcutter sup:

port, one movable toward and from the other, of bracin members securedto the upper portions 0% the blank carrier and cutter support andconnected together to permit relative movement, one of the bracingmembers having rack and pinion connection with its support to permitadjustment.

' In Witness whereof, we have hereunto signed our names. 7

ARTHUR L. STEWART, EDWARD W. BULLOCK. SCHUYLER H; EARL.v

